In general, light treatment is used for various purposes such as treatment of diseases such as neonatal jaundice, psoriasis, and acne, relief to pain and beauty. Green light beams and blue-white light beams are used for treatment of the neonatal jaundice, ultraviolet light is used for psoriasis treatment, and blue light beams, red light beams, and yellow light beams are used for acne treatment. In addition, various light sources are used depending on the application.
For example, in a case of using a light source such as an excimer lamp and an arc lamp, a treatment area is disposed at a certain distance from a fixed light source and irradiated with the light beams. However, since the light beams also hit on an area other than the treatment area in this method, it is demanded to take measures such as covering the area other than the treatment area with a light shielding object such as an eye mask for protecting the eyes. In addition, for curved parts such as hands and legs, since irradiation intensity varies depending on a location of the treatment area due to an angle and distance to the light source, it is difficult to uniformly irradiate the treatment area with the light beams. Furthermore, since such a lamp type apparatus is large and many auxiliary apparatuses such as a power supply and a cooling apparatus are demanded, a large installation space is demanded and price is high.
In addition, in a case where a light source such as a laser is used, since the light beams irradiated to the treatment area becomes spot light beams, it is demanded that the spot light beams are scanned in order to irradiate the treatment area of a large area with the light beams, so that an apparatus becomes complicated and expensive.
Furthermore, in a case where an apparatus that irradiates a surface with the light beams by utilizing an optical fiber is used, since efficiency of transmitting the light beams to the optical fiber is relatively low, irradiation power tends to be lowered, and thus it is suitable for only a relatively long treatment.
From the background as described above, there is a demand for a flexible light source for light beam treatment which can cover the treatment area while keeping a certain distance along the treatment area.
Here, a light-emitting diode (LED) is relatively smaller than other light sources, and it is possible to irradiate the treatment area having a curved surface with the different numbers of elements and different arrangement and the like with the light beams.
Therefore, with respect to the demand, the following PTLs using LEDs as the light-emitting sources are disclosed.
In PTL 1, a light irradiation apparatus in which a laser and an LED as the light-emitting source are disposed on a flexible substrate and which winds around the treatment area to be used is disclosed.
In PTL 2, a light irradiation apparatus for a face in which an LED as the light-emitting source is disposed on a flexible substrate and which covers the face in use is disclosed.
In PTL 3, a flexible light irradiation apparatus in which a large number of LEDs serving as a light-emitting source are arranged on a flexible substrate and which is wrapped around the treatment area, irradiating the wrapped treatment area with the light beams is disclosed.
In PTL 4, on the premise of application to the head, a light irradiation apparatus in which an LED serving as the light-emitting source is disposed inside a cap is disclosed.
In PTL 5, a light irradiation apparatus in which an LED serving as the light-emitting source is disposed of a flexible substrate and a light-transmitting material is interposed between the treatment area and the LED such that heat generated from the LED is transmitted to the treatment area is disclosed.
In NPL 1, a methicillin-resistant Staphylococcus aureus (MRSA) infection skin ulcer treatment method using LED near-ultraviolet light is described.